In general, it is known that the tip of a ski is exposed to many vibration phenomena. These vibrations are caused by the fact that the ski is moving over a surface containing obstacles which raise the end of the ski because of its relative flexibility. On the other hand, gravity tends to pull the tip of the ski down, causing chattering phenomena to occur.
These chattering phenomena may extend for varying lengths of time depending on the mechanical properties of the ski and especially on its stiffness and damping.
It is easily understood that these chattering phenomena are not propitious to good control of the gliding board and accordingly, many damping devices have been proposed to limit the amplitude and above all the duration of the vibration phenomena affecting the tip of the board.
One interesting solution was proposed in document FR 1 407 710 which describes a ski with a damping system comprising an arm of which one end
is integral with a fixed point in the front part of the ski. The rear part of this arm is integral with a hydraulic device comprising a piston and whose movement is ensured by the arm according to the deformation of the ski.
Accordingly, the upward or downward movements of the front end of the ski are braked in the same way by the action of the hydraulic actuator.
The symmetrical behaviour of this damping action, for upward or downward movements, is not entirely satisfactory. Indeed, if the damping becomes excessive, it tends to obstruct the downward movements of the tip of the ski thus delaying its recovery of a position in contact with the ground. Conversely, when damping is insufficient, the upward movements of the board are not braked sufficiently.
In other words, it can be understood that a compromise must be found in choosing the damping value to obtain differentiated behaviour depending on whether the damping movements are upwards or downwards.
A more fully integrated system is described in document U.S. Pat. No. 7,296,818 but it operates according to a similar principle, incorporating the same drawbacks, however.